With concerns about viruses and bacteria at an all-time high, scientists have begun looking for new ways to deter their spread, and are looking to the natural world with a view to copying nature’s designs.
One strategy has been to create surfaces so moisture-repellent that these microbes find nothing to cling to. These surfaces are called hydrophobic (“they hate water”) and researchers seek to mimic natural materials produced by animals that can repel water very effectively, as well as bacteria.
A team of researchers from the University of Illinois at Urbana-Champaign and the US Army Corps of Engineers Construction Engineering Research Laboratory have identified a cheaper and faster way to produce these surfaces.
The lotus leaf is a particularly famous example of hydrophobic material, but scientists have also discovered that the wings of cicadas naturally repel water. Marianne Alleyne, a professor of entomology at the University, has co-led a new study on how we can make the same surface structure cheaply and quickly.
In the study posted on Nano LettersAlleyne and his colleagues presented a simplified version of a manufacturing process called nanoprint lithography. Using this process, the team designed a template to copy the wing structure of Neotibicen pruinosus, an annual cicada found in the Midwest.
“We chose to work with the wings of this species of cicada because our previous work demonstrates how the complex nanostructures in its wings provide an exceptional ability to repel water. That is a very desirable property that will be useful in many materials engineering applications, from airplane wings to medical equipment. “ Alleyne said.
The team’s new process involves using cheaper materials (commercial nail polish, for example) rather than more expensive materials. The technique also avoids higher temperatures that would damage natural samples used by equipment in the past.
To make the template, which can be copied and printed, the team applies a quick-drying nail polish directly onto a cicada wing, which is then allowed to cure at room temperature. Once completed, the template can be coated with a polymer or metal, with the interior dissolved, leaving only the metal or polymer replica.
This newer and simpler method is the first step towards the invention of new ultrahydrophobic surfaces with a variety of applications, the most important of which may be to prevent bacteria and viruses from establishing and spreading.
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